Help Diagnose Front-end Sound

[ejoness]

1997 2WD Explorer

With vehicle standing still, brake on, start engine and shift from P to R, metallic rattle under front starts up, but lessens in a few seconds. Shifting to N, noise stops. Shifting to D, noise starts again, but less loud and lessens quickly.

Last week, I briefly had a flashing Overdrive light, but it hasn't repeated.

Transmission fluid level seems good -- maybe even a little high.

Any ideas for me?

Thank you!

-Eric

 

[deadernie]

Rattling noise you describe sounds like a heat shield on the exhaust.

 

[pcam13]

Yep. Check your cat heat shields. Apply the park brake and leave it in drive and youll be able to hop out and diagnose which heat sheild is rattling. Apply hose clamps around the one in which is leaking. Done it for years.

 

[pcam13]

double post oops.

 

[ejoness]

Thanks... I've just gone under to test the heat shield idea. I can't rule it out yet, but I'm hearing a "pebble shaking in a can" sound from the area of the cat. It seems to me to be more "inside" than "outside".

What do you think about a failing catalytic converter with a broken piece being blown around in there?

Is that consistent with:
P -> no sound
R -> rattle
N -> no sound
D -> rattle then no sound after a few seconds?

Would the airflow vary with the different gear states enough to suggest the intermittent sounds?

 

[Turdle]

Had this on my 98, they found a piece of metal in the cat, which had broken away and was floating inside. Hit the cat with your hand and see if it rattles.